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Biomedical subjects

L L Hansen

Publications and source records attributed to L L Hansen.

At least 91 records · Page 5Linked to original sources
PubMed1990

Analysis of a highly immunodominant epitope in the human immunodeficiency virus type 1 transmembrane glycoprotein, gp41, defined by a human monoclonal antibody.

A human monoclonal antibody, 41-7 [immunoglobulin G1(kappa)], directed against the transmembrane glycoprotein gp41 of the human immunodeficiency virus type 1 (HIV-1) has been produced by direct fusion of lymph node cells from an HIV-1-infected individual with a human B-lymphoblastoid cell line. The minimal essential epitope for 41-7 was mapped to a conserved seven-amino acid sequence, N-CSGKLIC-C, located within the N-terminal part of gp41. Antibodies blocking the binding of 41-7 could be detected in the serum of all HIV-1-infected individuals tested, irrespective of the stage of the infection. The epitope is located externally to the plasma membrane, and it is accessible to antibody in the native conformation of the glycoprotein. Despite this, no neutralizing activity of 41-7 could be demonstrated in vitro. These data indicate, directly and indirectly, that this immunodominant epitope on gp41, although exposed on the viral surface, elicits antibodies lacking antiviral activity and, hence, should be avoided in future vaccine candidates.

Amino Acid Sequence↗
PubMed1990

Haemorheological changes in patients with retinal vein occlusion after isovolaemic haemodilution.

In 83 patients with central retinal vein occlusion and branch vein occlusion we measured the haematocrit (HCT), plasma viscosity (PV), red cell aggregation (RCA), red cell filterability (RCF) and apparent whole blood viscosity (WBV). A control group (n = 41) was matched for sex, age, and cardiovascular risk factors. Measurements were performed before and after treatment with isovolaemic haemodilution (IHD). We found no significant differences between patients with retinal vein occlusion (RVO) and control subjects in haematocrit, plasma viscosity, red cell aggregation, and red cell filterability and no increased whole blood viscosity in the patient group. Patients with ischaemic retinal vein occlusion and non-ischaemic retinal vein occlusion did not show different haemorheological parameters either. After treatment with haemodilution, only the haematocrit and whole blood viscosity were significantly decreased, and there were no changes in plasma viscosity, red cell aggregation or red cell filterability.

Adult↗
PubMed1990

Marketing alternatives for hospitals to the nursing crisis.

The current nursing shortage problem as defined in this article, is the result of a supply and demand imbalance. The demand for nurses is growing at a faster rate than the supply. If strategies are not implemented to correct this imbalance the demand for nurses will continue to surpass the supply, negatively affecting access to and delivery of quality patient care. Factors contributing to the increased demand for nurses and the dwindling supply must be examined if solutions to the problem are to be found and implemented. Factors contributing to the growing demand for nurses include the decreasing use of ancillary personnel by hospitals in an effort to tighten their budgets; the impact of Medicare's prospective payment system on hospital lengths of stay; the increase in patient acuity with advances in medical technology; and alternative health care opportunities pulling nurses away from the hospital setting. The supply of RNs is shrinking in relation to demand because of low retention rates; declining nursing school enrollment; non-competitive wages; poor working conditions; alternative career opportunities for women; and the lack of power and support within the nursing profession. An active marketing approach that relies on this assessment of contributing factors has been formulated in an attempt to resolve the problem and meet the increasing demand. Recommendations have been made and ranked in the order of their priority and pros and cons established for each. The strategies developed have been divided into four basic marketing categories of product, price, place, and promotion. If the problem is to be resolved these strategies must be marketed to hospitals, their administrators, nurses, other allied health professionals, third party payors, educators, and the general public. The nursing profession itself must find the unity and strength within its own group of professionals to build political and economic powers to enhance their product. Nursing is at a crossroad. Much depends on how we cope with the current shortage and its related issues. Nurses have the opportunity to shape their future. Hopefully, with proactive strategies, the profession will transform from a passive role to an active, vital force of the health care environment. The authors believe that through our marketing approaches this can be accomplished.

Employee Incentive Plans↗
PubMed1990

[Hemorheologic parameters in patients with giant cell arteritis before and after treatment with steroids].

Basic hemorheological parameters like packed cell volume (PCV), plasma viscosity, red cell aggregation, red cell filterability and whole blood viscosity were measured in 18 patients (14 women, aged 75.4 years) with giant cell arteritis before and after treatment with steroids. The patient group was compared to controls (n = 27, age: 69.8 years) with matched age and cardiovascular risc factors. While no changes in red cell aggregation and filterability could be observed plasma viscosity was increased (1.59 +/- 0.14 mm2/s) by about 20%. The typical anemia of patients with giant cell arteritis (PVC: 0.38 +/- 0.05) prevented an increase in whole blood viscosity at high and medium shear rates (6.6 +/- 0.14 cP = mPas at 23/s). After a fortnight of systemic treatment with high doses of steroids the PCV had normalized and plasma viscosity was even lower than in controls. Thus the blood fluidity was improved as shown by a fall in whole blood viscosity (5.5 +/- 0.7 cP = mPas at 23/s). Results showed: (1) increased plasma viscosity probably induced by increased fibrinogen concentration and (2) an improvement in blood fluidity by treatment with steroids. As the plasma viscosity may participate in the deterioration of microcirculation in patients with giant cell arteritis, lowering the fibrinogen may possibly prevent a further decrease in visual acuity during the first few days of steroid treatment.

Aged↗
PubMed1990

Pyruvate dehydrogenase deficiency caused by deletion of a 7-bp repeat sequence in the E1 alpha gene.

A 7-bp deletion in the X-chromosomal pyruvate dehydrogenase (PDH) E1 alpha gene was characterized in a female patient with the "cerebral" form of PDH deficiency. The mutation was localized using the chemical cleavage method and further characterized by application of the polymerase chain reaction and DNA sequencing. This 7-bp sequence is found in the normal gene as a direct tandem repeat. The deletion causes a change in the reading frame. Results have shown that the level of normal sized PDH E1 alpha in the fibroblast sample was approximately 30% of that of normal controls. This is consistent with normal transcription from the X chromosome carrying the nonmutated form of the E1 alpha subunit, as this chromosome is active in approximately 30% of this patient's cells. The severity of PDH E1 alpha deficiency in affected females is to a large extent dependent on the X-chromosome inactivation pattern in the brain. The clinical picture might therefore vary significantly between patients with the same mutation. We show that the 7-bp deletion must be a de novo mutation, because it is not present in the parent's X chromosomes. Furthermore, the deletion was not detected in chorionic villus samples in two subsequent pregnancies.

Chromosome Deletion↗
PubMed1989

Deuterium isotope effects as a tool in the study of ethanol oxidation in rat liver microsomes.

The apparent kinetic deuterium isotope effect (I) on the oxidation of ethanol to acetaldehyde by washed rat liver microsomes was measured with (1-R)-[1-2H2, 1-14C]-ethanol (I1) and [1-2H2, 2-14C]-ethanol (I2) as substrates by a competitive technique involving only measurements of radioactivity. The average values were for non-induced rats, I1 = 1.57 and I2 = 2.23. When these two substrates were used with stereospecific enzymes (alcohol dehydrogenase and catalase) a small secondary effect was observed, causing I2 to be about 10% higher than I1. With non-stereospecific systems I2 was much larger than I1, and the values were connected by a simple formula. This relation in combination with use of the inhibitors, sodium azide and thiourea, made it possible to calculate tentatively the contribution to microsomal ethanol oxidation of catalase, a non-identified stereospecific enzyme, and non-stereospecific catalytic systems, as well as the isotope effects of the latter two systems. Measurements were made in microsomes from normal, phenobarbital treated, and acetone treated rats. For the stereospecific component an isotope effect of 1.4-1.5 was calculated for all three groups. For the non-stereospecific enzyme in acetone treated rats a value of 4.0 was found. Both the other groups showed a value about 2.7. The activity of the non-stereospecific system was about twice the normal in barbiturate treated, and 3 times the normal in the acetone treated group, where it contributed 70% of the total activity. The isotope effects on the changes in ethanol oxidation (the 'differential isotope effect') caused by inhibitors and activators were utilized to decide whether inhibitors were specific for a single reaction. Thus azide while inhibiting catalase completely, also inhibited other reactions. The large increase (5-6 times) in rate caused by Fe-ESDTA has an I2 of 1.6, equal to that for oxidation of ethanol by hydroxyl radicals.

Acetone↗
PubMed1989

A randomised prospective study of treatment of non-ischaemic central retinal vein occlusion by isovolaemic haemodilution.

In a randomised study 25 patients over 50 years of age with non-ischaemic central retinal vein occlusion (CRVO) were assigned to either a treatment (14 patients, isovolaemic haemodilution) or a control group (11 patients, no treatment). After three months eight eyes in patients with haemodilution improved, whereas none of the untreated eyes had better visual acuity (p less than 0.01). Thirteen haemodiluted and 11 control patients could be observed for one year. Six eyes of the haemodiluted patients retained a better visual acuity, whereas no improvements had occurred in the control group (p less than 0.025). In fluorescein angiography the lowering of the packed cell volume to 35-32% accelerated the time of maximal venous filling (tmvf) from 17.4 (SEM 1.4) s to 11.4 (SEM 0.9) s (p less than 0.005). In patients with non-ischaemic CRVO without treatment the passage time did not change. The shortened tmvf reflects a higher blood velocity. Thus isovolaemic haemodilution improves the visual prognosis in non-ischaemic CRVO probably by inducing a higher blood fluidity, which results in higher blood velocity, at least in areas of compromised retinal microcirculation.

Aged↗
PubMed1989

Effect and compatibility of isovolaemic haemodilution in the treatment of ischaemic and non-ischaemic central retinal vein occlusion.

In a prospective study, 48 eyes with non-ischaemic and 35 with ischaemic central retinal vein occlusion (CRVO) were treated by isovolaemic haemodilution (IHD). Two or more cardiovascular risk factors were present in 42% of patients with non-ischaemic and in 69% of patients with ischaemic CRVO (p less than 0.025). Nevertheless, IHD in no case caused serious cardiovascular complications. Minor problems were short fainting spells in 5% and a general weakness in 16% of the haemodiluted patients. The effect of IHD was measured by determining the time of maximal venous filling (tmvf) in fluorescein angiographies. Lowering the packed cell volume to 32-35% accelerated the tmvf from 18.4 +/- 1.61 to 13.1 +/- 1.0 s (p less than 0.001) in eyes with non-ischaemic CRVO and from 24.5 +/- 1.2 to 14.8 +/- 1.3 s (p less than 0.001) in eyes with ischaemic CRVO. After 3 months, an increase in visual acuity had occurred in 27% of eyes with non-ischaemic CRVO and in 48.5% with ischaemic CRVO. These improvement rates could nearly be maintained after 1 year. 59% of eyes with non-ischaemic and 25% with ischaemic CRVO were able to read (visual acuity greater than or equal to 6/15) after 1 year.

Cardiovascular Diseases↗
PubMed1989

[Retinitis in AIDS patients: diagnosis, follow-up and treatment].

Of 147 patients with AIDS (Walter Reed 3-6), 28 showed signs of retinal infection. Toxoplasmic retinochoroiditis had developed in 5 eyes of 4 patients, whereas cytomegalovirus (CMV) retinitis occurred in 40 eyes of 24 patients. All patients with toxoplasmosis complained of visual symptoms at the first visit, but only 60% of patients with CMV retinitis had ocular symptoms at this time. The important problems involved in making a timely and correct diagnosis (early CMV retinitis vs cotton wool spots vs toxoplasmic retinitis; significance of laboratory data) are presented and discussed. The course of CMV retinitis is sometimes fast and devastating and requires immediate treatment to prevent blindness in patients who are in otherwise still fair general health. Eighteen patients (28 eyes) were treated by intravenous ganciclovir (DHPG) for 1-9 months. Initial therapy (10 mg/kg body wt., 2-4 weeks) led to regression of fundus lesions in all eyes. Under maintenance treatment (5 mg/kg BW body wt., 5 times a week), 14 eyes still demonstrated significant regression or cicatrization of the lesions, 9 eyes showed little progress and 5 eyes moderate recovery. However, 8 of 12 untreated eyes became legally blind before the patient died. None of the 23 treated eyes with useful initial visual acuity (greater than or equal to 0.2) lost visual function. Only in three cases did the drug have to be stopped because of serious side effects (severe leukopenia, pancytopenia, psychosis). Toxoplasmic retinochoroiditis healed in all affected eyes after specific treatment (pyrimethamine, sulfamethoxydiazine, clindamycin, and spiramycin in double or triple combination).(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1987

[Combination of phacoemulsification and trabeculectomy. Results of a retrospective study].

Combined trabeculectomy and phacoemulsification was performed on 21 eyes with poorly controlled glaucoma (15 open-angle glaucomas, 5 capsular glaucomas, and one secondary glaucoma) and coexisting cataract. In 20 of these eyes there was severe glaucomatous damage of the optic nerve with visual field loss. With the procedure used by the present authors there was a higher incidence of choroidal detachments, whereas other complications occurred at a lower rate than reported by other authors combining cataract extraction and trabeculectomy. Mean IOP was lowered from 25.7 +/- 6.1 to 17.1 +/- 3.2 mmHg after 18 months. Thirteen patients (62%) required no medication, while 5 (24%) required additional therapy for sufficient control of IOP (less than or equal to 21 mmHg). The results indicate that the combined phacoemulsification and trabeculectomy procedure may be a useful approach in eyes with severe glaucomatous damage and cataract.

Aged↗
PubMed1987

[Initial diagnosis of acquired immunologic deficiency syndrome (AIDS) by the ophthalmologist].

The authors report on two patients who presented with sudden loss of vision, due to irodocyclitis and retinochoroiditis in one patient and optic neuritis in the other. AIDS was diagnosed in both patients on the basis of a positive HIV antibody assay, lymphopenia, and a reduced helper-to-suppressor subset ratio. Soon afterwards, the patient with retinochoroiditis developed the full-blown picture of AIDS with cerebral involvement. Neither anticytomegaly treatment with DHPG nor triple therapy for toxoplasmosis was able to prevent the fatal course. The patient died within six months. In contrast, the patient with optic neuritis recovered full visual acuity. So far there has been no relapse, nor any opportunistic infection in other organs.

Acquired Immunodeficiency Syndrome↗
PubMed1985

A randomised prospective study on treatment of central retinal vein occlusion by isovolaemic haemodilution and photocoagulation.

Thirty eight patients with ischaemic and non-ischaemic central retinal vein occlusion were evaluated for the effect of isovolaemic haemodilution. They were allocated at random to a haemodilution group (19 patients, panretinal photocoagulation and isovolaemic haemodilution) and a control group (19 patients, panretinal photocoagulation). Haematocrit was lowered in steps to 30 to 35% in the haemodilution group by repeated exchanges of whole blood for plasma and dextran (MW 40 000) and kept at this level for a period of six weeks. The haemodilution did not lead to serious complications. Three months after starting the treatment eight of 19 patients with haemodilution showed a better visual acuity, whereas only one of 19 control patients had improved. Seven of 17 patients with haemodilution, but only one of 17 control patients, retained a better visual acuity after one year. In the haemodilution group there were fewer patients with macular fibrosis and more with only minor foveal changes. The haemodilution seems to be more effective in patients with ischaemic than with non-ischaemic central retinal vein occlusion. It is concluded that isovolaemic haemodilution improves the visual outcome of patients with central retinal vein occlusion, probably mediated by enhanced retinal blood flow.

Aged↗
PubMed1984

Relationship between peritubular membrane potential and net fluid reabsorption in the distal renal tubule of Amphiuma.

Amphiuma kidneys were isolated and perfused with modified Ringer solution and peritubular and transepithelial membrane potentials (p.d.s) in distal tubules measured with micro-electrodes during rapid changes of luminal electrolyte concentrations. Peritubular membrane potential and net fluid reabsorption (split-oil-droplet method) were also measured with and without application of various drugs known to alter transport. Raising the luminal sodium concentration from 10 to 100 mM reversibly increased the peritubular p.d. The magnitude of the peritubular p.d. was a saturable function of luminal sodium concentration. In the presence of chloride in the lumen the peritubular hyperpolarization following increased luminal sodium could be inhibited by luminal amiloride (10(-4)M). Sodium-induced hyperpolarization of the peritubular p.d. could be completely inhibited by 10(-5)M-ouabain. Adding amiloride (10(-4)M) to the luminal fluid rapidly and reversibly depolarized the peritubular p.d. and inhibited fluid reabsorption. Addition of amphotericin B (20 micrograms/ml) to the luminal perfusion solution had no effect on peritubular p.d. at 100 mM-luminal NaCl but at 10 mM-NaCl, peritubular p.d. hyperpolarized. Fluid reabsorption was stimulated (with 100 mM-NaCl in the lumen). Addition of amphotericin when the tubule was perfused on both sides with solutions containing a constant potassium concentration of 78 mM and a variable sodium concentration ranging from 7.8 to 34.5 mM revealed strong dependence of the peritubular hyperpolarization on the sodium concentration. Luminal furosemide (10(-4)M) and chlorothiazide (10(-4)M) and peritubular ethacrynic acid (10(-4)M) all reduced fluid reabsorption but hyperpolarized the peritubular p.d. The data suggest the presence of an electrogenic sodium transport process in the peritubular membrane that directly contributes to the generation of the peritubular potential. In addition, chloride transport has an important role in determining this potential.

Absorption↗
PubMed1984

Tethered versus loose sows: ethological observations and measures of productivity: II. Production results.

Production results as well as behaviour were registered in an experiment with tethered and loose housed sows. In two of the experimental groups the sows were neck-tethered during pregnancy. In one of these two groups the sows were also neck-tethered in a farrowing crate during farrowing and lactation (exp. group TT), while in the other group they were loose (exp. group TL). In the last two of the four experimental groups the sows were loose in social groups of 2 to 5 during pregnancy. In one of these two groups the sows were also loose during farrowing and lactation (exp. group LL), while in the other group they were neck-tethered in a farrowing crate (exp. group LT). There were no statistically significant differences between the four groups in number of born alive or stillborn. Group LT, where the sows were tethered in the farrowing and lactation period only, had a significantly higher number of sows needing birth assistance and a tendency towards a higher incidence of MMA complex than the other three groups. No significant differences between the four groups were found in either number of pigs per litter at 7.21 and 56 days (weaning), or total number of dead or percentage dead pigs in the lactation period, or in number of traumatic pigs or pigs with arthritis. The group LT, however, had a strong tendency towards lower weaning weight per litter than the other groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗